scholarly journals Accelerated Microbial Reduction of Azo Dye by Using Biochar from Iron-Rich-Biomass Pyrolysis

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1079 ◽  
Author(s):  
Wenbing Tan ◽  
Lei Wang ◽  
Hanxia Yu ◽  
Hui Zhang ◽  
Xiaohui Zhang ◽  
...  
Keyword(s):  
Azo Dye ◽  
Removal Rate ◽  
Shewanella Oneidensis ◽  
Microbial Reduction ◽  
Biomass Pyrolysis ◽  
Surface Functional Groups ◽  
Redox Active ◽  
Fe Content ◽  
Orange G ◽  
Discharging Capacity

Biochar is widely used in the environmental-protection field. This study presents the first investigation of the mechanism of biochar prepared using iron (Fe)-rich biomass and its impact on the reductive removals of Orange G dye by Shewanella oneidensis MR-1. The results show that biochars significantly accelerated electron transfer from cells to Orange G and thus stimulated reductive removal rate to 72–97%. Both the conductive domains and the charging and discharging of surface functional groups in biochars played crucial roles in the microbial reduction of Orange G to aniline. A high Fe content of the precursor significantly enhanced the conductor performance of the produced biochar and thus enabled the biochar to have a higher reductive removal rate of Orange G (97%) compared to the biochar prepared using low-Fe precursor (75%), but did not promote the charging and discharging capacity of the produced biochar. This study can prompt the search for natural biomass with high Fe content to confer the produced biochar with wide-ranging applications in stimulating the microbial reduction of redox-active pollutants.

scholarly journals Prominent Conductor Mechanism-Induced Electron Transfer of Biochar Produced by Pyrolysis of Nickel-Enriched Biomass

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 573 ◽  
Author(s):  
Wenbing Tan ◽  
Renfei Li ◽  
Hanxia Yu ◽  
Xinyu Zhao ◽  
Qiuling Dang ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Redox Reactions ◽  
Plant Biomass ◽  
Low Cost ◽  
Shewanella Oneidensis ◽  
Microbial Reduction ◽  
Electron Shuttle ◽  
Electron Shuttles ◽  
Ni Content ◽  
Redox Active

Biochar is redox-active and can function as a sustainable electron shuttle in catalyzing relevant redox reactions. It plays a crucial role in environmental remediation. In this work, we used different-nickel (Ni)-level biochars produced by the pyrolysis of plant biomass with correspondingly different Ni levels as extracellular electron shuttles for microbial reduction of ferrihydrite by Shewanella oneidensis MR-1. A high Ni level of the precursor considerably enhanced the conductor mechanism of the produced biochar and thus enabled the biochar to catalyze increased microbial reductions of the Fe(III) mineral, but it did not promote the charging and discharging capacities of the produced biochar. This study can aid in the search for natural biomass with high Ni content to establish low-cost biochars with wide-ranging applications in catalyzing the redox-mediated reactions of pollutants.

Use of a sequencing batch biofilter for degradation of azo dyes (acids and bases)

2000 ◽  
Vol 42 (5-6) ◽  
pp. 329-336 ◽  
Author(s):  
M. Quezada ◽  
I. Linares ◽  
G. Buitrón
Keyword(s):  
Azo Dyes ◽  
Azo Dye ◽  
Degradation Rate ◽  
Removal Rate ◽  
Textile Effluent ◽  
Colour Removal ◽  
Substrate Degradation ◽  
Acids And Bases ◽  
Removal Efficiencies ◽  
Basic Red 46

The degradation of azo dyes in an aerobic biofilter operated in an SBR system was studied. The azo dyes studied were Acid Red 151 and a textile effluent containing basic dyes (Basic Blue 41, Basic Red 46 and 16 and Basic Yellow 28 and 19). In the case of Acid Red 151 a maximal substrate degradation rate of 288 mg AR 151/lliquid·d was obtained and degradation efficiencies were between 60 and 99%. Mineralization studies showed that 73% (as carbon) of the initial azo dye was transformed to CO2 by the consortia. The textile effluent was efficiently biodegraded by the reactor. A maximal removal rate of 2.3 kg COD/lliquid·d was obtained with removal efficiencies (as COD) varying from 76 to 97%. In all the cycles the system presented 80% of colour removal.

scholarly journals Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

2021 ◽  
Vol 18 (13) ◽  
pp. 6807
Author(s):  
Jingtao Duan ◽  
Zhiyuan Xu ◽  
Zhen Yang ◽  
Jie Jiang
Keyword(s):  
Molecular Weight ◽  
Electron Transfer ◽  
Humic Acids ◽  
Weight Fraction ◽  
Electrochemical Analysis ◽  
Microbial Reduction ◽  
Redox Potentials ◽  
Groundwater Environment ◽  
Redox Active ◽  
Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

Impact of Graphitic Structures in Pyrogenic Carbon on Microbial Reduction of Ferrihydrite

2021 ◽  
Author(s):  
wentao yu ◽  
baoliang chen
Keyword(s):  
Electron Transfer ◽  
Pyrolysis Temperature ◽  
Shewanella Oneidensis ◽  
Exchange Capacity ◽  
Microbial Reduction ◽  
Systematic Evaluation ◽  
Extracellular Electron Transfer ◽  
Pyrogenic Carbon ◽  
The Impact

&lt;p&gt;Pyrogenic carbon plays important roles in microbial reduction of ferrihydrite by shuttling electrons in the extracellular electron transfer (EET) processes. Despite its importance, a full assessment on the impact of graphitic structures in pyrogenic carbon on microbial reduction of ferrihydrite has not been conducted. This study is a systematic evaluation of microbial ferrihydrite reduction by Shewanella oneidensis MR-1 in the presence of pyrogenic carbon with various graphitization extents. The results showed that the rates and extents of microbial ferrihydrite reduction were significantly enhanced in the presence of pyrogenic carbon, and increased with increasing pyrolysis temperature. Combined spectroscopic and electrochemical analyses suggested that the rate of microbial ferrihydrite reduction were dependent on the electrical conductivity of pyrogenic carbon (i.e., graphitization extent), rather than the electron exchange capacity. The key role of graphitic structures in pyrogenic carbon in mediating EET was further evidenced by larger microbial electrolysis current with pyrogenic carbon prepared at higher pyrolysis temperatures. This study provides new insights into the electron transfer in the pyrogenic carbon-mediated microbial reduction of ferrihydrite.&lt;/p&gt;

scholarly journals Spin-Dependent Electron Transport through Bacterial Cell Surface Multiheme Electron Conduits

2019 ◽  
Author(s):  
Suryakant Mishra ◽  
Sahand Pirbadian ◽  
Amit Kumar Mondal ◽  
Moh El-Naggar ◽  
Ron Naaman
Keyword(s):  
Electron Transport ◽  
Cell Surface ◽  
Bacterial Cell ◽  
Shewanella Oneidensis ◽  
Extracellular Electron Transfer ◽  
Long Distance ◽  
Force Microscopy ◽  
Bacterial Cell Surface ◽  
Redox Active ◽  
Gain Energy

Multiheme cytochromes, located on the bacterial cell surface, function as long-distance (> 10 nm) electron conduits linking intracellular reactions to external surfaces. This extracellular electron transfer process, which allows microorganisms to gain energy by respiring solid redox-active minerals, also facilitates the wiring of cells to electrodes. While recent studies suggested that a chiral induced spin selectivity effect is linked to efficient electron transmission through biomolecules, this phenomenon has not been investigated in the extracellular electron conduits. Using magnetic conductive probe atomic force microscopy, Hall voltage measurements, and spin-dependent electrochemistry of the decaheme cytochromes MtrF and OmcA from the metal-reducing bacterium <i>Shewanella oneidensis</i> MR-1, we show that electron transport through these extracellular conduits is spin-selective. Our study has implications for understanding how spin-dependent interactions and magnetic fields may control electron transport across biotic-abiotic interfaces in both natural and biotechnological systems.

Microbial reduction of zearalenone by a new isolated Lysinibacillus sp. ZJ-2016-1

2018 ◽  
Vol 11 (4) ◽  
pp. 571-578 ◽  
Author(s):  
J.Q. Wang ◽  
F. Yang ◽  
P.L. Yang ◽  
J. Liu ◽  
Z.H. Lv
Keyword(s):  
Gene Sequence ◽  
Removal Rate ◽  
Reproductive Toxicity ◽  
Luria Bertani ◽  
Microbial Reduction ◽  
Rrna Gene ◽  
Whole Cells ◽  
Gene Sequence Analysis ◽  
Heating Treatment ◽  
Food And Feed

Zearalenone (ZEA) has a strong reproductive toxicity. Reducing and eliminating ZEA from food and feed is of great significance. The aim of the present study was to screen bacteria for reduction of ZEA. A pure culture of strain ZJ-2016-1, identified as Lysinibacillus sp. by 16S rRNA gene sequence analysis methods, was isolated from chicken large intestine digesta and showed to be effective in eliminating ZEA; 32 μg/ml of ZEA in Luria-Bertani medium was completely removed within 48 h by whole cells of ZJ-2016-1. Heating treatment significantly reduced the removal rate of ZEA from 95.8 to 10.4% in the culture supernatant, suggesting that the microbial reduction of ZEA was likely enzymatic. The optimal conditions for the microbial reduction of ZEA by ZJ-2016-1 included temperature of 37 °C and pH of 7.0. To sum up, these results indicated that the Lysinibacillus strain is a promising bacterium resource for reducing ZEA, and its genes and enzymes involved in microbial reduction of ZEA should be further explored.

Photocatalytic degradation of azo dye in TiO2 suspended solution

2001 ◽  
Vol 43 (2) ◽  
pp. 313-320 ◽  
Author(s):  
C.-H. Hung ◽  
P.-C. Chiang ◽  
C. Yuan ◽  
C.-Y. Chou
Keyword(s):  
Reaction Time ◽  
Light Intensity ◽  
Photocatalytic Degradation ◽  
Azo Dye ◽  
Batch Reactor ◽  
Reaction Rates ◽  
Pseudo First Order Reaction ◽  
Degradation Rates ◽  
Orange G ◽  
Degradation Of Azo Dye

The photocatalysis of azo dye, Orange G, by P-25 anatase TiO2 was investigated in this research. The experiments were conducted in a batch reactor with TiO2 powder suspension. Four near-UV lamps were used as the light source. The experimental variables included solution pH level, amount of TiO2, illumination light intensity, and reaction time. A pseudo-first order reaction kinetic was proposed to simulate the photocatalytic degradation of Orange G in the batch reactor. More than 80% of 10 mg/L Orange G decomposition in 60-minute reaction time was observed in this study and fast decomposition of Orange G only occurred in the presence of both TiO2 and suitable light energy. Faster degradation of Orange G was achieved under acid conditions. The degradation rates of Orange G at pH = 3.0 were about two times faster than those at pH = 7.0. Faster degradation of azo dye was observed for greater irradiated light intensity and more TiO present during the reaction. The reaction rates were proportional to TiO2concentration and light intensity with the power order of 0.726 and 0.734, respectively.

Preparation of MgCl2-Coated Activated Carbon and its Adsorption Behavior of Azo Dye from Aqueous Solution

2009 ◽  
Vol 79-82 ◽  
pp. 295-298
Author(s):  
Jin Xiang Sun ◽  
Hai Zeng Wang ◽  
Bao Wei Sun
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Specific Surface ◽  
Pore Size ◽  
Azo Dye ◽  
Removal Rate ◽  
Weak Acid ◽  
Adsorption Behavior ◽  
Optimum Conditions ◽  
Mgcl2 Solution

The preparation of MgCl2/AC composite and its adsorption behavior of azo dye from aqueous solution were investigated. The pore size of the new kinds of adsorbent increased with increasing the dosage of MgCl2 solution, while specific surface area decreased. The removal rate of Weak Acid Red 2R from aqueous solution on the MgCl2/AC composite was 93.4 % at the optimum conditions of the preparation: activated carbon with 2 M MgCl2 solution at 110°C for 2 h.

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